James h



1. H. MGSHER. Press'ure Gage.

Patented Apri!` 5, 1859.

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J'AMES H. MOSHER, OF NEW' YORK, N. Y., ASSIGNOR TO HIJSELF ANI) ANSON T. COLT, GF SAME PLACE.

STEAM-PRESSURE GAGE.

Specification of Letters Patent No. 23,530, dated April 5, 1859.

To all whom it may] concern:

Be it known that l, JAMES H. Mosnnn, oit the city, county, and State of New York, have invented a new and useful improvement in Pressure-Gages; and l do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawing, forming part of this specification, in which a vertical section ot' a steam-gage having my improvement is represented.

My invention relates to mercurial gages which have their index tubes closed at the top.

lt consists in certain means by which provision is made for the charging of such gages in a proper manner by persons having no previous practice in charging gages, and while said gages are in their places attached to boilers; also, tor renewing' the air in the index leg from time to time as may be desirable; also, for cleaning out the index tube when necessary.

'llo enable others to make and use my invention, l will proceed to describe its construction and operation.

it is the glass tube or index leg of the gage, and B the back tube or leg, both secured. at theirI lower ends in a cast iron box C, which unites said lower ends, and both entering an upper box l), which merely serves to hold them in place. rlhe glass tube il, which constitutes the index leg, consists ot a st 1aight piece of ordinary glass tubing open tln'oughout but the upper end of said tube is iitted with a valve E, which is composed of an inverted metal cup filled with india rubber, a., and furnished with a stem which passes through a hollow screw F, which is screwed into the box D, to secure the valve in place and make it close the top ot the tube A. The face of the 'valve E, is so formed as not to enter the tube and compress the air therein as it closes, as it would do it made conical. The back leg B consists ot an iron tube, having its upper end screwed to connect the steam pipe, which pipe should be fitted with a cock to shut ott the steam when desired. Exactly on a level with or immediately above the zero point of the index leg, the back leg B is itted with an air valve c, by which to admit air into or permit the escape of steam or water from said leg; the said Valve having a screwed stem working in a female screwed socket attached to the leg, and being opened and closed by turning a head with which it is provided outside of the gage. The communication between the bottoms ot the two legs A, and B, is formed by drilling a hole from the i'ront of the box C, right across or tlnough the socket d, in which the lindex tube is received; and into the socket e, in which the back tube is received; and by tap ping a serewthread in said hole and screwing thereinto a screw plug Gr, which has one or more notches 'or grooves g, cut across its threads in a. spiral direction to form a nar row passage between the sockets el, e, and the said notch or groove being cut like the groove of a left-handed tap in order that, when the plug is screwed out, it may bring out from the female screw thread any dirt which might tend to choke the passage.

To fill the gage, it must be in an uprightposition but it may be attached to or detached from the boiler; but if attached to the boiler, the cock in the steam pipe which connects with the back leg should be closed. The screw F, and the Valve E, are to b-e taken out and the Valve c, opened; and the mercury may then be poured in at the top ot the tube A, till it reaches the Zero point of the index; the height to which it rises in the back leg B, being of course the same as in the front leg, for the two legs are in communication and both are open to the atmosphere. The gage being thus charged, the valve E is to be replaced and secured to close the top of the index leg, the valve c, is to be closed and if the gage is not set up in its place a cap should be screwed on to the top ot the back leg. It too much mercury should have been put in, the surplus may be let out before closing the Valves E, c, by unscrewing the plug G, far enough to let it run out. The gage, it will be thus seen, is filled with as little trouble as a common open siphon gage and without any of the diiiiculty attendant upon the filling of closed tube gages in which the air above the mercury in the index tube is compressed or rarelied when the mercury is at zero; and all air contained within the tube remains at the pressure of the atmosphere so long as no steam is on the back leg, and always ret-urns to such pressure when the pressure upon the back leg ceases and the Valve c, is opened to let out any steam or water 0i condensation therefrom and admit air there' into. If the air and mercury become displaced in the gage by transporting it from place to place they will not fail to return to their proper positions if the gage be held upright and the valves E, and c., be loosened.

lVhen the air in the index leg may be supposed to have lost its elasticity a fresh and proper supply may be admitted while there is no steam pressure on the back leg by simply opening the valves E, .and c, which brings the mercury to Zero in the index leg and lls the space above with air at atmospheric pressure. When it is desired to cleanthe tube A, the valve E, is taken out and a swab is run down the inside of said tube, without taking out the mercury.

rlfhe method of forming the passage between the two legs by the spiral groove in the screw plug G, possesses the advantage over the use oi a screw with its threads filed 0E or reduced all around, as commonly used in the same place, of serving to withdraw any dirt that may collect in and tend to choke the passage.

I do not claim the useV of a valve to close the top of the index leg of the gage or a valve in the back leg.

What I claim as my invention, and desire to secure by Letters Patent, is

So applying the valves E, 0, in combination with each other that the gage may be charged while both legs are open to the atmosphere, as described, and that the air above the mercury in the index tube may be caused to have an ordinary atmospheric pressure While the mercury is at Zero7 and there is only the pressure of the atmosphere on the back leg.

JAMES H. MOSHER. l/Vitnesses:

HENRY T. BROWN, W. HAUFF. 

